328 



Messrs. A. Harden and W. J. Young. 



[Feb. 12, 



phosphate. This introduces an uncertainty, as the additional phosphate 

 constantly being formed in (b) might accelerate the auto-fermentation to 

 such an extent as greatly to increase the total evolved. In order to avoid 

 this cornplication as far as possible, a second experiment was carried out with 

 yeast-juice vphich was prepared from yeast previously kept in the pressed 

 condition at 20° for 20 hours, the juice being then treated with living yeast 

 for three hours before use in order to ferment away any free sugar. In tliis 

 way a juice of small auto-fermenting power was obtained. Unfortunately 

 the fermenting power of the juice towards sugar was also considerably 

 lowered by this treatment. 



Experiment 11. — Yeast-juice, treated as described above, was employed, and two 

 quantities were taken — 



a. 30 c.c. of the juice -I- 30 c.c. of a solution of potassium liexosephosphate, equivalent 



to 134 '6 c.c. of carbon dioxide. 



b. 30 c.c. of the juice -f- 30 c.c. of water. 



These mixtures were incubated in presence of toluene, and the gas evolved and 

 phosphate formed were estimated. 





Carbon dioxide. 



Pliosphate rendered free, 

 as MgoP-^O;. 



b 



c.c. 

 52 -3 

 14 5 



gramme. 

 0 -0944 

 0 -0262 



0 -2058 

 0 -0792 



37 -8 



0-0682 



0 -1266 



Here the fermentation of tlie luixosephosphate has yielded at least 

 0"0682 gramme of carbon dioxide and 01266 gramme of phosphate as 



Mg^PoO;. 



The fact that hexosephosphate is fermented by zyinin has been observed 

 by Iwanoff'* and this observation has been confirmed l)y the authors. 



IV. Natvrc of the Chemical Chaixjc involved in AlcoJiolic Fermentation. 

 The facts (1) tliat alcoholic fermentation occurs according to tlie equation : 

 2CflHi20« -f 2r04HI{, = 2CO2 -f 2C2H«0 2H2O + C6H,o04(r04E2)2, 

 and (2) that tlie hcxosephosphates produced from ghicose, fructose, and 

 mannosc appear to be identicalf have an important bearing on the cliemical 

 interjjrctation of the decjompoHition by fermentation of the hexosea into 

 carbon dioxide and alcoliol. it has been pointed out by Young (loc. rit.) that 



* 'Centr. Bakt.,' Abt. II, 1909, vol. 24, p. 1. 



+ Yomif,', ' Hoy. Soc. Proc.,' B, l !»()!», vol. 81, p. 528. 



